Some types of locomotives often rely on multiple traction motors to drive one or more wheels attached to one or more axles in order to propel the locomotive. A typical North American locomotive has six to eight axles and each axle is usually attached to two wheels. During operation, individual traction motors may utilize electricity produced by one or more generators powered by one or more engines of the locomotive. The traction motors use the electricity to create mechanical rotation that is transferred to a drive motor shaft and a set of reduction gears. Most commonly, a set of reduction gears includes a pinion gear and a bull gear. The drive motor shaft has a pinion gear attached to the end of the shaft opposite the motor. The pinion gear engages the bull gear, located inside the gear case. This transfer of rotation from the drive motor shaft to the pinion gear and bull gear creates the necessary torque to propel the locomotive and possibly one or more cars attached to the locomotive down the rail.
During traction motor operation the drive motor shaft may incorporate the use of drive end bearings to facilitate the rotation. Furthermore, the high rate of rotation experienced by the drive motor shaft, drive end bearings, and reduction gears may require lubrication in order to keep the parts functioning properly. A typical traction motor arrangement may incorporate a common lubricant sump located in the gear case. The lubricant in the sump may be used for lubricating drive end bearings, reduction gears and other components of the traction motor. The bull gear is enclosed in the gear case and rotates through the lubricant sump picking up lubricant in the gear teeth and splashing the lubricant within the gear case. Some of the lubricant splashes into a receptacle that feeds a lubrication pathway from the gear case into the drive end bearing. The lubricant that enters into the receptacle moves across the drive end bearing to provide lubrication to the bearing and any excess lubricant is returned to the sump in the gear case through a return duct.
This type of lubrication arrangement, however, has some limitations. In some situations the rotation speed of the drive motor shaft may push the limits of the common lubricant shared by the drive end bearing and the reduction gears. Under these operating conditions, the increased rotation speed of the drive motor shaft may require use of a lower viscosity lubricant for the drive end bearing. However, use of a lower viscosity lubricant is not ideal for proper lubrication of the reduction gears. Furthermore, placing a lower viscosity lubricant in the gear case sump creates additional difficulties in ensuring the gear case is leak proof. A typical gear case design has numerous interfaces and other features and using a lower viscosity lubricant makes it increasingly difficult to ensure the gear case is leak-proof. As a result, alternative traction motor designs are sought that can provide separate lubricant sources for the drive end bearing and reduction gears.
An alternative lubricant device is described in U.S. Pat. No. 5,038,631 (the '631 patent). The '631 patent discloses a lubricant restricting device for a traction motor drive gear assembly that is positioned between a mounting plate and the back side of a pinion gear. The restricting device is molded from an elastomeric or semi-elastomer material. The device has a base and a barrier structure formed by a lip or series of lips. The base is circular in shape and the lips are formed in spaced apart concentric circles. To reduce the lubricant flow between the pinion gear and mounting plate the lips extend to make contact with the pinion gear.
While in some applications the lubricant device described in the '631 patent may aid in diverting the flow of lubricant in a traction motor gear case, the device does not provide a self-contained lubrication device for a drive motor bearing. Rather, the device seeks to limit the flow of lubricant between the pinion gear and the mounting plate of the gear case in order to minimize the migration of gear lubricant into the armature shaft bearing assembly. Additionally, the device described in the '631 patent fails to disclose an additional lubricant source for the drive motor bearing, nor does it disclose a circulation path for the drive motor bearing lubrication.
The self-contained lubrication device of the present disclosure is directed at solving one or more of the problems set forth above and/or other problems associated with the prior art.